In an image, a texture is, for example, fine patterns or the like in an image and frequently is a signal of a high frequency (high frequency band). For example, in an encoding method based on FFT (Fast Fourier Transform) (frequency band resolution) such as AVC (Advanced Video Coding), an image is degraded mainly from high frequency components, and therefore, (part of) a texture of the image is lost and the picture quality of an image obtained on the decoding side is degraded.
As a method for suppressing degradation of the picture quality caused by loss of a texture of an image, a method is available by which, in order to restore a texture lost upon encoding of an image, a texture of an image is transmitted separately in addition to encoded data of an encoded image (for example, refer to PTL 1 or NPL 1).
For example, in the method based on NPL 1, texture components are removed from an original image in an encoding apparatus and the original image after the texture components are removed is encoded. Then, in the encoding apparatus, a small amount of texture components (image) and synthesis parameters are transmitted together with encoded data obtained by encoding.
On the other hand, in a decoding apparatus, the encoded data is decoded and the texture components from the encoding apparatus are synthesized with a decoded image obtained by the decoding using the synthesis parameters and then a restoration image obtained by restoring the original image is generated.
In PTL 1, a technology is proposed in which, in an encoding apparatus, a texture (texture pattern) is reduced and transmitted and, in a decoding apparatus, the reduced texture is enlarged by a super-resolution technology.